The goal of this project is to develop a mobility task that can be used to complement those currently used to assess function in older adults. This research will develop a task that simplifies the equipment needed while preserving the psychometric properties of the CAR task, an objective performance test that uses an aluminum frame mock-up of an automobile and measures the time needed to open the door, get into a bucket seat, close the door, re-open the door, and step out, immediately moving to an erect position. The new task would incorporate elements of lateral mobility, stooping, weight shift, and transfer, similar to the current demands of the CAR task, while using simple, portable equipment that can be reproduced by many researchers. Previous research has shown that the CAR task has some properties that do not exist in tasks such as time to climb stairs (a maximal performance task), preferred walking speed (a self-paced performance task), or in a self-report of disability. For example, it was have found that a balance measure (functional base of support in the anterior-posterior direction) was predictive of decline in CAR task performance, but not in self-reported disability, stair climb time, or preferred walking speed. From a practical perspective, difficulty or inability to enter and exit a car as a passenger can severely limit the ability of a frail older person to travel. Criteria for the task to be developed are that it is reliable, valid, easy to administer in the clinic/community, and sensitive to change via physical activity intervention strategies. The measurement properties of the new task will be developed and evaluated in several sub-studies over a 1-2 year period. First, test-retest reliability of the new task will be examined in 50 older adults, utilizing persons whose functional status ranges from non-disabled to severely disabled. Ceiling and floor effects will be evaluated at this time and modifications to the test will be made if needed. Second, a known groups test will be performed. Two groups of 25, one with no/little disability, the other with moderate/severe disability, will be identified to examine the validity of the test. Third, correlation analyses will be conducted between the new test and measures of strength, balance, and functional performance. Fourth, a sample of participants will be examined in a 2-D frontal plane kinematic analysis to determine if poorer performance on the task is associated with changes in movement strategies. In future work, the sensitivity to change of the task will be examined by incorporating it into a community-based intervention study.